data consistency - european space agency · 22-oct-2014 rain forest mask amazon river rio negro...
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22-Oct-2014
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Data consistency
Presented byXavier Neyt / RMA
22-Oct-2014
Overview
ERS2 calibration
Pattern evolution over time on the rain forest• ERS2• ASCAT-A
22-Oct-2014
ERS2 calibration
Correction of the flatness of the antenna pattern
Using the rain forest, assuming “flat” behaviour• Considering a mask to remove unstable rain forest areas
22-Oct-2014
ERS-2 EvolutionGamma nought over the rainforest
Relatively flat pattern (except aft beam)
No clear tendency in time
Stability within 0.4 dB over 16 years
1996; 2001; 2002; 2011
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ASCAT EvolutionGamma nought pattern over the rainforest
2008; 2009; 2011; 2013
Sloped pattern
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Conclusions
Gamma nought pattern• ERS-2: flat • ASCAT-A: sloped pattern
No clear temporal tendency in the data• ERS-2 relatively stable (within 0.4 dB) over 16 years • ASCAT relatively stable (within 0.2 dB) over 5 years
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Backup slides
Backup slides
22-Oct-2014
Rain forest mask
Amazon river
Rio Negro
Motivation• Residual components at orbital frequency in spectral analysis of
sigma0 over rain forest• Indicates that the rain forest is not spatially
homogeneous Constructions
• Exclude unstable areas and areas whose sigma0 is too different from mean sigma0 (towns and rivers)
22-Oct-2014
Rain forest mask
Red: Trees Yellow: high backscatter (towns,…) Green: low backscatter (rivers,…)
Amazon river
Rio Negro
These rivers should be removed from the calibration area
22-Oct-2014
Rain forest mask